Monday, June 23, 2014

Shoutcast/Icecast Protocol

The Shoutcast/Icecast streaming protocols began in 1998 as a simple hack to stream MP3 radio stations. A company called Nullsoft (now part of AOL), using a slightly customized version of the HTTP protocol (called the ICY protocol, with a URL like icy://http://www.masteringinternetvideo.com:8200), created the Shoutcast server, which can send or receive streamed MP3 or pretty much any streamable audio or video codec.

The first version of the protocol was so simple it consisted of merely MP3s shoved one after another. Later versions of the protocol added support for sending track names, titles, and more, along with the songs and having the client players display them. Finally, very stable video streaming features were added.

An explosion of different players that can play these streams as well as a variety of services that could reflect the streams resulted in the rapid improvement and de facto standardization of the Shoutcast protocol. In fact, there are more players for Shoutcast MP3 streams than any other kind of player. Every streaming MP3 player on the market—including the big three media players as well as Apple's iTunes—plays Shoutcast audio streams. Looked at it in this light: Shout-cast is in some ways the most cross-platform, interoperable protocol for streaming audio. Currently, however, the video playback is limited to WinAmp and other NSV (Nullsoft Video) players. This allows digital audio content, primarily in MP3 or HE-AAC format,